1. Field of the Invention
The present invention relates to method and device for loading and unloading a film onto and off of a rotary drum in exposure/recording apparatus, such as a raster plotter employed for defining wiring patterns of, e.g., printed wiring boards (PWBs), a precise exposure device for photomechanical process, which device controls exposure beams in an on-off manner as a function of supplied dot pattern data to perform main scanning and vertical scanning thereby to print desired patterns on photosensitive material, and a color scanner for use in graphic arts.
2. Description of the Prior Art
To automatically load and unload a film onto and off of a rotary drum in an exposure/recording apparatus, there are many expedients known in the art, among which is an apparatus disclosed in Japanese Patent Publication (examined) No. 52(1977)-42086. This known apparatus achieves the automatic loading and unloading of a film by employing a cassette in which the film is accommodated. A disadvantage of this apparatus is that the film is the cassette must be replaced with a fresh film every time the exposure is finished. The replacement of films must be carried out in a darkroom separated from the operation room. To reduce the inefficiency resulting from the frequent replacement two cassettes are used, that is, one cassette is used for the scanning operation while the other one is used for the replacement the films. In any case, however, the frequent replacement of films is labor- and time-consuming, thereby leading to the increased production cost.